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Re: FW: LC Comments: Web Method Feature

From: Mark Baker <distobj@acm.org>
Date: Wed, 3 Jul 2002 13:35:08 -0400
To: "Williams, Stuart" <skw@hplb.hpl.hp.com>
Cc: "'xml-dist-app@w3.org'" <xml-dist-app@w3.org>
Message-ID: <20020703133508.I10550@www.markbaker.ca>

On Wed, Jul 03, 2002 at 05:27:02PM +0100, Williams, Stuart wrote:
> >From [1]:
> <quote>
>   Axiom
>      In HTTP, GET must not have side effects.
>   The introduction of any other method apart from GET which has no side
>   effects is also incorrect, because the results of such an operation 
>   effectively form a separate address space, which violates the
> universality.
> </quote>
> ...care to comment?

Yes, Tim needs to focus on the issue, not a symptom of it. 8-)

See http://lists.w3.org/Archives/Public/www-tag/2002Jan/0075

> > I have to admit to being confused by the suggestions to derive the
> > method.  Why is that desirable? 
> Well we continue to have the two views... the chameleon view and the
> messaging/tunneling view. 

Where did "messaging" come from there?  I think the chameleon view is
as much about messaging as the tunneling view ... at least as far as
the underlying protocol permits.

> We are close to a position that admits both views. The Web Method features
> enables the chameleon to take on the REST resource state manipulation and
> retrieval view. Mandating its use (needlessly IMO) denies the
> messaging/tunneling view.

For HTTP, yes it does, more or less.  It encourages SOAP implementations
to expose the method in some manner to developers, thereby breaking the
notion of SOAP as a layer when bound to HTTP.  This is a good thing IMO.
As you know, I've been saying that SOAP isn't a layer (with HTTP) for
some time.

If developers want to use the tunnelling approach, they can use TCP.
That's the right thing to do on many levels, IMO.

> > A developer has to know what methods are being invoked.  How else can they
> get their job done?
> Developers of binding implementations will know... the binding specification
> will tell them.
> Developers of SOAP applications will know the semantics of the features they
> use, because the feature specification will tell them.

But you need more than features to use an application protocol, you need
application semantics.  Are you suggesting that they be exposed as

> If the resource state
> view is important to them, they will use the Web Method feature. If they
> think more in terms of message exchange (in a binding agnostic fashion) Web
> Method is unlikely to be a feature they will use.

If the resource state view is not important to them, why are they using

Mark Baker, CTO, Idokorro Mobile (formerly Planetfred)
Ottawa, Ontario, CANADA.               distobj@acm.org
http://www.markbaker.ca        http://www.idokorro.com
Received on Wednesday, 3 July 2002 13:24:14 UTC

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